New algorithm for calibration of instantaneous cutting-force coefficients and radial run-out parameters in flat end milling

Abstract

It is well recognized that the cutter run-out appearing in the milling process will cause an uneven redistribution of the instantaneous uncut chip thickness through the cutter flutes and thereby will generate an irregular distribution of the cutting forces in different tooth periods. This work aims to develop a new approach able to identify the cutter radial run-out and cutting-force coefficients in the flat end milling. It is shown that the total cutting forces can be considered as the sum of a nominal component that is independent of the run-out plus a perturbation component induced by the run-out. Mathematical formulations of both components are developed, accounting for the cutting geometry and the radial run-out parameters. Firstly, to calibrate the cutting-force coefficients, a generic procedure is proposed using the instantaneous value of the nominal component instead of the average value. Secondly, considering the fact that the perturbation component of the cutting force depends non-linearly upon the run-out parameters, the identification of run-out parameters is carried out by solving the linearized equation. In the identification procedure, some key techniques such as the calculation of the immersion boundary at any cutting instant and the reasonable selection of the depth of cut are discussed in detail. Finally, based on simulation and experimental results, the validity of the identification approach is demonstrated.

Error compensation in the five-axis flank milling of thin-walled workpieces

“…A two-flute high-speed steel (HSS) end mill with a diameter of 12 mm and helix angle of 45° is used in the final machining. The cutting coefficients for this couple of cutter and workpiece pair are identified by the method introduced in Wan et al, 23 and the identification results are listed as follows: K tc = 926 . 5 N / m m 2 , K rc = 526 . 8 N / m m 2 , K ac = 252 N / m m 2 , K te = 14 . 1 N / mm , K re = 12 N / mm and K ae = 1 . 4 N / mm .…”

Cutting forces modeling for micro flat end milling by considering tool run-out and bottom edge cutting effect

“…It can be seen from the cutting forces model in section “Development of the cutting forces model,” the tangential, radial and axial cutting forces are approximately linear to the chip load, which is equal to S ( t ) = ∑ i , j [ t c , i , j dz ] . 31 Therefore, the shearing cutting force coefficients related to the flank edge, K tc , K rc and K ac , can also be calibrated by transforming the cutting forces in x -axis, y -axis and z -axis directions into the tangential, radial and axial directions with the method in equation (27) and the calibrated tool run-out parameters.…”

“…6. Substitute the above calculated cutting forces coefficients from equation (31) into equation 22, and then the convergence for the solution of equation 31is calculated as…”

Modeling of flatness errors in end milling of thin-walled components

“…The approach correlates cutting forces with uncut chip area determined geometrically using Mechanistic constants. 6 The model has matured over the years by incorporating effects of various process characteristics such as size effects, 7 cutting edges, 8 cutter run-out, 9 and so on. It can be inferred that the Mechanistic model can predict cutting forces with reasonable accuracy over a wide range of cutting conditions.…”